In nature, most bacteria exist as biofilm communities, residing in a self-generated protective nanoscale scaffold of proteins, sugars, lipids, and extracellular DNA that defends against environmental rigors. Biofilm formation is essential for bacterial adhesion and colonization of both natural and man-made surfaces. These highly evolved extracellular matrices hold untapped potential as a beneficial nanobiotechnology engineering platform. There is a significant body of work that investigates the use of biofilms for beneficial purposes such as wastewater treatment and biotransformations, but these efforts focus on the use of naturally occurring organisms that happen to have evolved various desired qualities. Efforts to rationally engineer the structure of biofilms at the molecular level have been absent. To date, there exists no robust and broad technology for the facile engineering of biofilm components.